Respostas fisiológicas de dois genótipos de Crambe (Crambe abyssinica Hochst.) ao déficit hídrico

• Autor(a) principal: Martins, Rodrigo Fantin Alves
• Data de Publicação: 2015
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da Universidade Federal do Espírito Santo (riUfes)
• Texto Completo: http://repositorio.ufes.br/handle/10/10025
• topic: Photosystem II; Chlorophyll a fluorescence; JIP-test; Drought tolerance; Recovery; Fotossistema II; Fluorescência da clorofila a; Teste – JIP; Tolerância ao déficit hídrico; Recuperação; Plantas - Efeito da seca; Clorofila; Ecofisiologia vegetal; Fluorescência; Agronomia; 57

Drought stress is one of the main environmental factors that limit growth and yield of plants. The objective of this study was to evaluate and compare the effects of induced drought stress and recovery in Crambe abyssinica Hochst plants using chlorophyll a fluorescence as an analytical tool. The plants of the cultivar FMS Brilhante and lineage FMS CR1101 were subjected to water stress by withholding water for seven days, followed by a period of three days of rehydration. For the analysis of chlorophyll a fluorescence, fully expanded young leaves were selected and adapted to the dark for 20 min. Fluorescence measurements of chlorophyll a was performed using a HandyPEA fluorometer. Were also made measures of the relative leaf water content (RWC), the stomatal conductance (gs) and biomass. Under drought stress, there was a reduction in the relative leaf water content (RWC) and stomatal conductance (gs), with full recovery after rehydration of plants. There was more root growth in FMS Brilhante during the imposition of water deficit. Both materials showed a decrease in the transport of electrons from the absorption until the reduction of the intersystem acceptors. However, on the seventh day of water deficit was observed in FMS Brilhante, increase in fluorescence signal only between FJ and FI steps, indicating the decrease of electron transport between QA and intersystem. The cultivar FMS Brilhante showed better energy connectivity (L-band) between independent subunits of photosystem II (PSII) and less inactivation of the complex evolution of oxygen (Kband). On the other hand, the lineage FMS CR1101 showed better results for the parameters that measure the quantum yield of the reduction of the final acceptor of photosystem 1 (FSI) (fRO), the efficiency with which an electron moves after QA - (?EO ) and the efficiency with which an electron from the intersystem reduces the final acceptor of FSI (?RO). The lineage showed also better results for the photochemical performance index (PItotal) during the rehydration period. Despite FMS Brilhante plants have presented higher root growth and better photochemical activity of PSII, the lineage showed better increment of photochemical activity of the FSI.